Lossy compression techniques require methods to effectively encode images at lower bit rates without sacrificing significant image quality. Fixed rate compression schemes generally have poor image quality at rates significantly below four bits per pixel. Some existing variable rate compression techniques, like Joint Photographic Experts Group (JPEG), apply some form of transform and quantization.
Some methods of reducing the amount of data to be stored after compression may involve storing the data in a sparse manner and interpolating the results. Existing methods generally have not provided good levels of image quality, and in some cases may also introduce potentially undesired image artifacts (e.g., high frequency noise).